Ultrasound-intensified Leaching of Gold from a Refractory Ore

Abstract

The effect of ultrasonic energy on the pretreatment and leaching of gold from the refractory ore was investigated. Firstly, the refractory ore was pretreated with sodium hydroxide under ultrasound. Secondly, the pretreated ore was leached under ultrasound. The leaching ratio of gold decreased with increasing of the ultrasound pretreatment time from 1 to 5 h and the NaOH concentration from 5 to 20 wt%. The ultrasound increased remarkably the leaching ratio of gold when the pretreated ore was subjected to ultrasound leaching. The results showed that the appropriate acoustic power was a requirement during the ultrasound-intensified leaching. The leaching ratio of gold increased with an increasing of NaCN concentration from 6 to 18 kg/t. The results demonstrated that the ultrasound is a viable extractive metallurgy technique in pretreatment and leaching for the refractory gold ores.

A Study on the Mechanism and Kinetics of Ultrasound-Enhanced Sulfuric Acid Leaching for Zinc Extraction from Zinc Oxide Dust

“…Therefore, the 2–15 min stage is selected for fitting the experimental data. Similar research methods were applied in the study of Wang et al [ 39 ] and Gui et al [ 41 ].…”

“…Under the mechanical action, through agitation and flow in the leaching solution, the ultrasound stirs the liquid intensively, reduces the diffusion resistance, and accelerates the mass and heat transfer to accelerate the diffusion and dissolution process of the medium, Through the thermal effect, the ultrasonic energy is continuously absorbed by the medium and converted into heat energy, which further promotes the reaction. Ultrasound-enhanced leaching provides a very special new physical environment for the difficult or impossible reactions to realize under conventional conditions, and thus, to a certain extent, the leaching conditions are improved, the reaction time is shortened, the recovery rate of valuable metals is increased, and an efficient metallurgical process of energy saving and environmental protection is realized [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. Wang et al [ 37 ] reported enhanced zinc leaching kinetics from zinc residues augmented with ultrasound.…”

“…The research results show that ultrasonic-assisted leaching is a suitable technique to improve the dissolution of ZnFe 2 O 4 , which represents the main obstacle during conventional leaching. In addition, based on the advantages of using ultrasound in strengthening the leaching process, ultrasonic technology has been widely used in the treatment of metals such as copper (Cu) [ 39 ], uranium (U) [ 40 ], gold (Au) [ 41 ], silver (Ag) [ 42 , 43 ], and germanium (Ge) [ 44 , 45 ], and has achieved relatively significant leaching effects.…”

Review of Ultrasound-Assisted Recycling and Utilization of Cathode Materials from Spent Lithium-Ion Batteries: State-of-the-Art and Outlook

“…It is important to note that the presence of ultrasound can lead to changes in the pH value and temperature of the solution, especially when a high ultrasound power is applied . For example, the excessive increase in the solution temperature can destroy leaching reagents and decrease the cavitation intensity in metal leaching processes. − Thus, future studies should further illustrate the roles of pH and temperature in the ultrasound-assisted recycling and utilization of cathode materials from SLIBs.…”

Effective removal of As from a high arsenic-bearing ZnSO4 solution by ultrasonic enhanced ozonation in a one-pot method

“…According to Yan et al, US can increase the dissolution rate of valuable metals (Li, Ni, Co, and Mn) in waste lithium batteries by over 95% under optimal conditions [37] . The experimental results of Zhang et al showed that US can increase the leaching concentration of gold in refractory gold ore by 18 kg/t from 6 kg/t with NaCN [38] . Masoum et al used ultrasonic and peroxide assisted sulfur leaching to make the recovery of vanadium and yttrium in fly ash reach 100% and 97% respectively.…”